We present XMM-Newton observations of the 569 sec period system RX J1914+24 (V407 Vul). This period is believed to represent the binary orbital period making it an ultra-compact binary system. By comparing the phase of the rise to maximum X-ray flux at various epochs (this includes observations made using ROSAT, ASCA and Chandra) we find that the system is spinning up at a rate of 3.17+/-0.07x10^{-12} s/s. We find that the spectra softens as the X-ray flux declines towards the off-phase of the 569 sec period. Further, the spectra are best fitted by an absorbed blackbody component together with a broad emission feature around 0.59keV. This emission feature is most prominent at the peak of the on-phase. We speculate on its origin.
@article{arxiv.astro-ph/0412284,
title = {XMM-Newton observations of the ultra-compact binary RX J1914+24},
author = {Gavin Ramsay and Pasi Hakala and Kinwah Wu and Mark Cropper and K. O. Mason and F. A. Cordova and W. Priedhorsky},
journal= {arXiv preprint arXiv:astro-ph/0412284},
year = {2009}
}